Vignette issue gets worse with f/11Can see it in the raw files in various RAW converters.incedible that its happening with both bodies I know!Lighting set up has been tried and tested. No matter where I frame - even putting the right top corner in the brightest hot spot the vignette is still there. Not evident in clear blue skies but will test this further tomorrow.

Doesn't matter how bright the light is - if you don't see the problem without flash illumination but do see it with flash illumination, on two different bodies, that suggests the problem is the flash illumination, not the cameras. The fact that it gets worse at f/11 (where you've killed any ambient contribution) further supports the idea that it's a strobe/triggeing issue. My 2¢...

Looking back at the original post, the shots are at 1/200 s which is the Xsync speed of the 5DIII. Despite assertions that, "Sync speed all ok," and, "Lighting set up has been tried and tested," I think the signs point to a flash sync problem.

Using my cheap radio flash trigger with Alien Bees, my 5D3 won't synch at 1/200. If I keep it at 1/160th, it works 99% of the time. When it doesn't work, I get an artifact a lot like those in the photos above.

Since the action is stopped by the strobes (at least in my otherwise dim studio) I don't worry about the exact shutter speed.

neuroanatomist I will test your theory tomorrow.this is what I shoot most of the time....for clean detail and sharpness in the feet the shutter speed does seem to matter - these feet are moving at 100kms an hour at least.

for clean detail and sharpness in the feet the shutter speed does seem to matter - these feet are moving at 100kms an hour at least.

1/200 s isn't nearly fast enough to freeze the motion of something moving that fast. As was pointed out earlier, it's the strobe(s) that are stopping the action. The slowest studio strobes have a flash duration of 1/500 s, and most are much faster than that (output power affects duration of most monolights only a little). Speedlites have a flash duration that's proportional to output power - on low power settings they can go shorter than 1/30,000 s duration (ganged speedlites on low power are used to freeze the wings of hummingbirds in flight, which are a lot faster than your dancers' feet - even the max shutter speed of 1/8000 s isn't fast enough).

When the flash duration is much shorter than the shutter speed (which it always is unless you're using a system with completely electronic shutter or a leaf shutter), the only thing shutter speed affects is the relative contribution of ambient light. If you are using a narrower aperture, the strobe is going to overpower the ambient, and a shutter speed between 1/60 s and 1/200 s makes exactly zero difference in the ability to freeze fast motion.

Set your shutter speed to 1/160 s (1/125 s may be necessary for some trigger setups), and you should be fine.

Dependent on the strobe type and power setting, the sync speed may not be the "actual" sync speed. Though the body max sync's at 1/200, if you have wireless vs wired sync, full power vs 1/2 power, Broncolor vs Buff, etc., your sync speed may be well below that.

I've done my share of dance shots, for a few theatre companies around here. I shoot Broncolor, with Pocketwizards on a 1DMkIII/1DsMkIII setup. Yet, I still set my shutter speed to 1/125 or 1/60 and let my lighting freeze the subject's motion for me. If the ambient is low enough in the room (model lights to low ratio), they won't influence your shots at all.

The vignetting I see looks more like uneven illumination of the scene, but since you've revolved around the camera body, it looks more like the curtain getting in the way of the strobe peak/fall.

I dont know about the mark2, but pocket wizards, on my mark 3, claim to be 1/200 of a second sync speed, but in my tests, they are actually 1/160. if i do 1/200, they will get some darkening, although it would be more uniformed along that side. I dont shoot many high key shots so that could explain the unevenness a bit

It's a sync issue. My 5d2 as well as two fellow photographers 5d2s will not sync with strobes at 1/200th of a sec. If you go to 1/160th the vignette will disapear. It's quite annoying because I believe sync is listed at 1/200th but that just isn't the case.

The only thing I'm not sure of is if this is brought on with the age of the body (I feel as if I use to be able to get 1/200th sync) or if maybe its an issue with wireless syncing ( I use pcb radios ).

Very well known and documented symptom, particularly after the popularity of remote speedlites and the 5D MkII. It is just flash sync, as Neuro says, go to 1/160, make sure you use an aperture that kills all ambient and you will be good.

Got to be honest, this is something I would expect somebody shooting 5,000 images a day to be well aware of.

If you can't close your aperture and have to use 1/200 sec then just stand back and frame to crop, cropping and framing can be done automatically on import.

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Too often we lose sight of the fact that photography is about capturing light, if we have the ability to take control of that light then we grow exponentially as photographers. More often than not the image is not about lens speed, sensor size, MP's or AF, it is about the light.